1. Field of the Invention
The present invention relates to the field of displaying technology, and in particular to a light guide plate, a backlight module, and a liquid crystal display device.
2. The Related Arts
In the known liquid crystal displays, a side-edge backlight module is often composed of a light guide plate, a reflector plate arranged on a bottom surface of the light guide plate, and a light source arranged at a lateral side of the light guide plate. In the side-edge backlight module, light emitting from the light source transmits through the lateral side of the light guide plate to get into the light guide plate. The light is subjected to reflection by the light guide plate and grid dots formed on the bottom surface of the light guide plate to have a portion of the light project out of a front surface of the light guide plate, while a remaining portion of the light is reflected toward a surface of the bottom reflector plate to be reflected by the bottom reflector plate back into the light guide plate and then further reflected to project out of the front surface of the light guide plate. Further, the light that projects out of the front surface of the light guide plate is subjected to diffusion and convergence of a film arranged atop the light guide plate so as to make an optic image homogeneous and sufficient central brightness of the image. The optical film is generally a prism film and/or a brightness enhancement film.
In the prior art, the light guide plate is often made of polymethyl methacrylate (PMMA), of which light transmittance of 92% and refractive index is 1.49. Thus, when light passing through the light guide plate, an amount of 8% of the light energy is absorbed by the light guide plate and gets lost, making the image brightness lowered down. The lost light energy can only be supplemented by using optic films of which the gain is increased to around 10% and this increases the manufacturing cost.